Not any more. Recently a breakthrough discovery has been made that has the potential to rival the impact of the ammonium synthesis. When Fritz Haber discovered this process in the early 20th century, he single-handily vanquished famines from the developed world as subsequently fertilizer became an inexpensive commodity. This new discovery has the potential to do the same for thirst and droughts. It involves a surprising property of graphene and does justice to the hype that this miracle-material receives: Although graphene is usually hydrophobic it can be made to form capillaries that efficiently absorb water. Now researchers at the University of Manchester report having formed layers of graphene oxide that exploit this property to make efficient water filters on the molecular level.

These filters are reported to work astoundingly efficiently, keeping anything out above the size of nine Angstrom (9.0 × 10-10 m) at a speed comparable to an ordinary coffee filter. It is essentially sieving on the molecular level. This is not yet enough to remove ordinary sea salt, but the scientists, who just published their research in last week’s issue of Science, are confident that the material can be scaled down to this level.

If so, it will change the world. Desalination of sea water is currently only affordable to the wealthiest countries, as the required investments are staggering, and operating the necessary infrastructure is very energy intensive. For instance, Saudi Arabia recently commissioned the world’s largest desalination plant for US$ 1.46 billion. The scope of the project is impressive, yet this amount of money will still only suffice to supply one large city metropolis with enough water (~3.5M people).

According to a new report by the Worldwatch Institute, 1.2 billion people, or nearly a fifth of the world’s population, live in areas of physical water scarcity, i.e. places where there is simply not enough water to meet demand. Another 1.6 billion face economic water scarcity, where people do not have the financial means to access existing water sources. If this research succeeds in creating a material that can simply filter out sea salt, and if its production can be scaled up, then this scourge on humankind could be rapidly diminished.

If they scale this down, it’ll be almost like distilled water (maybe lithium will still get through), but it shouldn’t be too hard to combine several such molecular sieves in a way that there is still a small flow of larger minerals coming through (simplest way would be to just have a small surface area made of the existing material with the rest comprised of the finer filter.

@article{M.:2011qy,
Author = {Elimelech M. and Phillip W. A.},
Journal = {Science}, Number = {6043}, Pages = {712–717},
Title = {The future of seawater desalination:
energy, technology, and the environment},
Volume = {333},Year = {2011},
Annote = {“The energy demand for seawater desalination by state-of-the-art reverse osmosis is within a factor of 2 of the theoretical minimum energy for desalination, and is only 25% higher than the practical minimum energy for desalination for an ideal reverse osmosis stage. Because thermodynamics set the limit on the energy demand for the desalination step, we argue that future research to improve the energy efficiency of desalination should focus on the pretreatment and posttreatment stages.}}

Conclusion Neither graphene nor any other new membrane material can offer order-of-magnitude improvements in energy efficiency in desalination.

The entirety of Elimelech’s and Phillip’s article is well-worth reading by students of transport dynamics (both classical and quantum), as there are plenty of similarities between desalination technologies and quantum computation/simulation technologies.

Good point, there is obviously no way to get around paying the enthalpy price, but my understanding is that unlike reverse osmosis a system with such a graphene filter would operate at much smaller pressure. I.e. it seems conceivable that you could construct small filter systems that can be operated manually. If these could be mass produced it’ll have an enormous impact on the 3rd world.

Sure but beyond toy models we know that the Sky Voltage raises about 120 V/m. Every true antenna engineer knows that first hand. Radio musts and transmission lines can suffer kV surges.
Ain’t that a good alternative source at least for developing countries? How is it that there is no serious research on commercialisation?

Correct, but this is just like a dripping hoose. Eventually you can charge a bucket and perhaps an array of synchronized buckets could do the job but I cant’ say how efficient this could be from an engineering point. A large capacitance would probably be better and nowadays we have some nice 10 F rascals like this one